The present invention is directed to a sliding ring seal and, in particular, to a sliding ring seal comprising a counter ring and an adjusting ring that are interconnected so that they do not move relative to one another. The counter ring and adjusting ring enclose a shaft that is to be sealed. The counter ring and the adjusting ring are sealed with respect to each other and to the shaft by at least a first sealing ring made of an elastomeric material. The sliding ring seal of the present invention also includes a sliding ring. The sliding ring is axially aligned with and resiliently jointed to a housing in such a way that no relative motion between the sliding ring and the housing occurs. The connection between the sliding ring and the housing is sealed by at least a second sealing ring. The counter ring and the sealing ring have sealing surfaces that contact one another in a sealing manner under an elastic preload. The first and second sealing rings are arranged in a corresponding installation space; the installation space corresponding to the at least first sealing ring is formed between the counter ring and the adjusting ring, and the installation space corresponding to the at least second sealing ring is formed between the sliding ring and the housing.
Typical sliding ring seals are made from permeable elastomeric materials. The sealing rings are intended to seal against a particular medium; if the pressure brought against the sealing rings by the medium becomes too great, the medium begins to penetrate the elastomeric material that constitutes the sealing rings. If a sudden pressure drop occurs in the surroundings of the sealing ring after such a penetration has occurred, the medium that has penetrated into the sealing rings abruptly expands. As a consequence of this expansion, the sealing rings are damaged or even destroyed. This kind of event is called an "explosive decompression." In order to reduce the risk of an explosive decompression occurring, it is known to use O-rings having a reduced cross-section and, as a result, a reduced exposed surface area. The likelihood of explosive decompression is also decreased by using O-rings made of materials having very high permeability rates, such as costly silicone materials.
An object of the present invention is to provide sliding ring seals having sealing rings that need not be manufactured of such costly materials, but yet achieve at least the same degree of resistance to explosive decompression as the above-mentioned sealing rings, regardless of the material that constitutes the sealing rings of the present invention.